wpf 动画 - 鼠标按下事件不起作用

Posted 2023-02-19

【中文标题】wpf 动画 - 鼠标按下事件不起作用

【英文标题】：wpf animation -- mouse down event doesn't work

【发布时间】：2016-09-22 15:08:03

【问题描述】：

每次都有一个蓝色矩形从窗口的左侧向右移动不同的距离。

无论是单击矩形还是动画完成，矩形都会从左侧重新开始移动。

如果点击矩形，它的颜色会变成绿色，持续时间为0.3s。

但是 MouseDown 事件似乎没有启动 ColorAnimation 并且矩形的移动距离/持续时间也不正确。

private int i;
private Storyboard hitTargetStoryboard;
private List<double> disList;

private void Window_Loaded(object sender, RoutedEventArgs e)

    disList = new List<double>.......;  // init with a list of values.

    /* Create a rectangle */
    Rectangle rect = new Rectangle();
    this.RegisterName("rect", rect);
    rect.Height = this.ActualHeight;
    rect.Width = 50;
    Canvas.SetTop(rect, 0);
    Canvas.SetLeft(rect, 0);

    /* Fill rect with a solid brush */
    SolidColorBrush targetRectBrush = new SolidColorBrush(Colors.Blue);
    this.RegisterName("targetRectBrush", targetRectBrush);
    rect.Fill = targetRectBrush;

    /* Add mouse down event */
    rect.MouseDown += Rect_MouseDown;

    /* Add rect to Canvas */
    myCanvas.Children.Add(rect);

    /* Create ColorAnimation to change color smoothly */
    ColorAnimation hitCA = new ColorAnimation();
    hitCA.To = Colors.Green;
    hitCA.Duration = TimeSpan.FromSeconds(0.3);
    hitCA.Completed += HitCA_Completed;

    /* Create storyboard and add ColorAnimation to it */
    hitTargetStoryboard = new Storyboard();
    Storyboard.SetTargetName(hitCA, "targetRectBrush");
    Storyboard.SetTargetProperty(hitCA, new PropertyPath(SolidColorBrush.ColorProperty));
    hitTargetStoryboard.Children.Add(hitCA);

    i = 0;
    TargetAnimation(i);



/* move the rect from 0--disList[i] */
private void TargetAnimation(int i)

    (this.FindName("rect") as Rectangle).Fill = Brushes.Blue;
    DoubleAnimation da = new DoubleAnimation();
    da.From = 0;
    da.To = disList[i];
    da.Duration = TimeSpan.FromSeconds(5);

    Storyboard.SetTargetName(da, "rect");
    Storyboard.SetTargetProperty(da, new PropertyPath(Canvas.LeftProperty));
    Storyboard storyboard = new Storyboard();
    storyboard.Children.Add(da);
    storyboard.Completed += Storyboard_Completed;
    storyboard.Begin(this);


/* If rect clicked, it will change color to green */
private void Rect_MouseDown(object sender, MouseButtonEventArgs e)

    hitTargetStoryboard.Begin(this);


/* After color changed, rect starts over */
private void HitCA_Completed(object sender, EventArgs e)

    TargetAnimation(++i);


/* If rect not clicked, it will start over */
private void Storyboard_Completed(object sender, EventArgs e)

    TargetAnimation(++i);

更新：

删除:(this.FindName("rect") as Rectangle).Fill = Brushes.Blue;

添加：hitCA.From = Colors.Blue;

ColorAnimation 效果很好。

静止：

如果我删除Storyboard_Completed 或HitCA_Completed，rect 的移动顺利。而如果我两者都有，那么运动就会走错路。

更新 2：

编辑：storyboard.Begin(this, true) 在TargetAnimation(int i) 方法中。

在HitCA_Completed 方法中添加：stroyboard.Stop(this)。

如果不将isControallable设置为true，故事板将无法控制。

已解决

【问题讨论】：

它是从Window 派生的MainWindow 类的一部分。矩形是 System.Windows.Shapes.Rectangle。 @PetterHesselberg

【参考方案1】：

你的问题在这里：

(this.FindName("rect") as Rectangle).Fill = Brushes.Blue;

首先，将rect设为字段并直接设置Fill属性会容易得多：

rect.Fill = Brushes.Blue;

不过，这对您的彩色动画没有帮助。你已经设置了一个动画来使用targetRectBrush——它不再填充rect，因为你刚刚替换了它。删除那条线会为颜色设置动画。

更新

这是一个稍微调整的版本：

public partial class MainWindow

    private int i;
    private Storyboard hitTargetStoryboard;
    private List<double> disList;
    private Rectangle rect;

    public MainWindow()
    
        InitializeComponent();
        Loaded += Window_Loaded;
    

    private void Window_Loaded(object sender, RoutedEventArgs e)
    
        disList = new List<double> 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 ;  // init with a list of values.

        /* Create a rectangle */
        rect = new Rectangle();
        this.RegisterName("rect", rect);
        rect.Height = this.ActualHeight;
        rect.Width = 50;
        Canvas.SetTop(rect, 0);
        Canvas.SetLeft(rect, 0);

        /* Fill rect with a solid brush */
        SolidColorBrush targetRectBrush = new SolidColorBrush(Colors.Blue);
        this.RegisterName("targetRectBrush", targetRectBrush);
        rect.Fill = targetRectBrush;

        /* Add mouse down event */
        rect.MouseDown += Rect_MouseDown;

        /* Add rect to Canvas */
        myCanvas.Children.Add(rect);

        /* Create ColorAnimation to change color smoothly */
        ColorAnimation hitCA = new ColorAnimation
            
                From = Colors.Blue, // (Instead of setting Fill to Blue)
                To = Colors.Green,
                Duration = TimeSpan.FromSeconds(0.3),
                FillBehavior = FillBehavior.Stop, // Returns to Blue
            ;
        hitCA.Completed += HitCA_Completed;

        /* Create storyboard and add ColorAnimation to it */
        hitTargetStoryboard = new Storyboard();
        Storyboard.SetTargetName(hitCA, "targetRectBrush");
        Storyboard.SetTargetProperty(hitCA, new PropertyPath(SolidColorBrush.ColorProperty));
        hitTargetStoryboard.Children.Add(hitCA);

        i = 0;
        TargetAnimation(i);
    


    /* move the rect from 0--disList[i] */
    private void TargetAnimation(int i)
    
        i = i % disList.Count; // Don't overflow

        DoubleAnimation da = new DoubleAnimation
            
                From = 0,
                To = disList[i],
                Duration = TimeSpan.FromSeconds(5),
            ;

        Storyboard.SetTargetName(da, "rect");
        Storyboard.SetTargetProperty(da, new PropertyPath(Canvas.LeftProperty));
        Storyboard storyboard = new Storyboard();
        storyboard.Children.Add(da);
        storyboard.Completed += Storyboard_Completed;
        storyboard.Begin(this);
    

    /* If rect clicked, it will change color to green */
    private void Rect_MouseDown(object sender, MouseButtonEventArgs e)
    
        hitTargetStoryboard.Begin(this);
    

    /* After color changed, rect starts over */
    private void HitCA_Completed(object sender, EventArgs e)
    
        TargetAnimation(++i);
    

    /* If rect not clicked, it will start over */
    private void Storyboard_Completed(object sender, EventArgs e)
    
        TargetAnimation(++i);
    

您发现距离/持续时间有什么问题？

【讨论】：

我删除了该行并且 colorAnimation 有效。但我需要将矩形恢复为蓝色。我该怎么办？

另外，移动 rect 的 DoubleAnimation 在 rect 中途停止的 MouseDown 事件后效果不佳。

我已经更新了我的答案，将FillBehavior 设置为将颜色恢复为蓝色。我不明白你的运动有什么问题；当彩色动画完成时，您显式调用TargetAnimation。如果这不是你想要的，你可以完全放弃HitCA_Completed。

Storyboard_Completed 是在完成后重新开始移动的那个。 HitCA_Completed 是在彩色动画完成后重新开始运动的那个。如果我理解正确，您需要保留 Storyboard_Completed，但删除 HitCA_Completed...

你能解释一下“运行错误”是什么意思吗？可以想象，您需要在开始新动画之前停止任何正在运行的动画。以下是关于在代码中控制动画的相当不错的读物：msdn.microsoft.com/en-us/library/ms741997(v=vs.110).aspx